Google fit not counting steps when holding the smartphone

Hi,
I recently installed Google Fit on my smartphone but I noticed something strange.
The app is not counting steps when I have my mobile in hands, like when I answer to messages or when I'm on the phone.
However, the Samsung Health app is able to count the steps perfectely fine even when I have my smartphone in hands.
Is there a possibility to set Google Fit to count theses steps too ?

Thank you !